Power Converter
Enter a power value and choose your source and target units to convert instantly between watts, kilowatts, horsepower, and BTU per hour.
Converted value
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How the Power Converter formula works
Every unit routes through watts as a common base:
value_in_watts = value × factor_of_source_unit result = value_in_watts / factor_of_target_unit
For example, 1 mechanical horsepower = 745.7 watts and 1 BTU/hr ≈ 0.293 watts.
Step-by-step calculation
- Multiply the entered value by its unit's conversion factor to get watts.
- Divide that value by the target unit's conversion factor.
- Round to a sensible number of decimal places.
Worked example
Converting a 150 horsepower engine to kilowatts: 150 × 745.7 = 111,855 watts ≈ 111.9 kW.
Frequently asked questions
Is horsepower the same everywhere?
There are slightly different horsepower definitions (mechanical, metric, electrical) that vary by a small percentage — this calculator uses mechanical horsepower (745.7 W), the most common definition for engines and motors in the US.
What's BTU/hr commonly used for?
BTU per hour is a standard rating unit for air conditioners, furnaces, and heaters, describing how much heat energy the equipment can move or generate in an hour.